Assessing reproductive and endocrine parameters in male largescale suckers (Catostomus macrocheilus) along a contaminant gradient in the lower Columbia River, USA.

Persistent organochlorine pollutants such as polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (p,p'-DDE), and polybrominated diphenyl ethers (PBDEs) are stable, bioaccumulative, and widely found in the environment, wildlife, and the human population. To explore the hypothesis that reproduction in male fish is associated with environmental exposures in the lower Columbia River (LCR), reproductive and endocrine parameters were studied in male resident, non-anadromous largescale sucker (Catostomus macrocheilus) (LSS) in the same habitats as anadromous salmonids having conservation status. Testes, thyroid tissue and plasma collected in 2010 from Longview (LV), Columbia City (CC), and Skamania (SK; reference) were studied. Sperm morphologies and thyrocyte heights were measured by light microscopy, sperm motilities by computer-assisted sperm motion analysis, sperm adenosine triphosphate (ATP) with luciferase, and plasma vitellogenin (VTG), thyroxine (T4), and triiodothyronine (T3) by immunoassay. Sperm apoptosis, viability, mitochondrial membrane potential, nuclear DNA fragmentation, and reproductive stage were measured by flow cytometry. Sperm quality parameters (except counts) and VTG were significantly different among sites, with correlations between VTG and 7 sperm parameters. Thyrocyte heights, T4, T3, gonadosomatic index and Fulton's condition factor differed among sites, but not significantly. Sperm quality was significantly lower and VTG higher where liver contaminants and water estrogen equivalents were highest (LV site). Total PCBs (specifically PCB-138, -146, -151, -170, -174, -177, -180, -183, -187, -194, and -206) and total PBDEs (specifically BDE-47, -100, -153, and -154) were negatively correlated with sperm motility. PCB-206 and BDE-154 were positively correlated with DNA fragmentation, and pentachloroanisole and VTG were positively correlated with sperm apoptosis and negatively correlated with ATP. BDE-99 was positively correlated with sperm counts and motility; T4 was negatively correlated with counts and positively correlated with motility, thus indicating possible androgenic mechanisms and thyroid endocrine disruption. Male LSS proved to be an informative model for studying reproductive and endocrine biomarkers in the LCR.

Cushioned versus noncushioned centrifugation: sperm recovery rate and integrity.

It was hypothesized that optimal sperm recovery rate (RR) without damage to the sperm would be obtained after centrifugation without a cushion solution. Semen collected three times from six light breed stallions was extended to 25 × 10(6) sperm/mL and centrifuged at CON (noncentrifuged), 900NC (no-cushion), 900C (cushion), 1800NC, and 1800C × g for 10 minutes. Sperm concentration, motility (TM and PM), and intact plasma membranes (PLM) and acrosomes (ACR) pre- and postcentrifugation (D0) and after 24 hours (D1) of cooling were evaluated. The RR in the CON (100 ± 0.0), 900NC (93.7 ± 2.9), and 1800NC (96.7 ± 2.6) groups was significantly higher than the 900C (68.7 ± 4.6) and 1800C (79.6 ± 3.5) groups. The D0 TM and PM were not different between the CON, 900NC, 900C, and 1800C, but were lower for the 1800NC group. The D1 TM and PM of the 900NC (75.2 ± 3.8 and 71.1 ± 4.1) and 900C (76.2 ± 3.7 and 72.4 ± 4.0) groups were significantly higher than the 1800NC (71.7 ± 4.1 and 67.3 ± 4.4) and 1800C (71.6 ± 4.1 and 67.2 ± 4.4) groups, and the CON (66.2 ± 4.5 and 60.0 ± 4.8) group was significantly lower than the other groups. The D1 PLM of the CON, 900NC, 900C, 1800NC, and 1800C groups were not different. The ACR on D1 was significantly lower for the CON (93.0 ± 2.4) group compared with all other groups. Optimal RR preserving sperm integrity was obtained in the 900NC group.

Factors affecting sperm recovery rates and survival after centrifugation of equine semen.

Conventional centrifugation protocols result in important sperm losses during removal of the supernatant. In this study, the effect of centrifugation force (400 or 900 × g), duration (5 or 10 min), and column height (20 or 40 mL; Experiment 1); sperm concentration (25, 50, and 100 × 10(6)/mL; Experiment 2), and centrifugation medium (EZ-Mixin CST [Animal Reproduction Systems, Chino, CA, USA], INRA96 [IMV Technologies, Maple Grove, MN, USA], or VMDZ [Partnar Animal Health, Port Huron, MI, USA]; Experiment 3) on sperm recovery and survival after centrifugation and cooling and storage were evaluated. Overall, sperm survival was not affected by the combination of centrifugation protocol and cooling. Total sperm yield was highest after centrifugation for 10 min at 400 × g in 20-mL columns (95.6 ± 5%, mean ± SD) or 900 × g in 20-mL (99.2 ± 0.8%) or 40-mL (91.4 ± 4.5%) columns, and at 900 × g for 5 min in 20-mL columns (93.8 ± 8.9%; P < 0.0001). Total (TMY) and progressively motile sperm yield followed a similar pattern (P < 0.0001). Sperm yields were not significantly different among samples centrifuged at various sperm concentrations. However, centrifugation at 100 × 10(6)/mL resulted in significantly lower total sperm yield (83.8 ± 10.7%) and TMY (81.7 ± 6.8%) compared with noncentrifuged semen. Centrifugation in VMDZ resulted in significantly lower TMY (69.3 ± 22.6%), progressively motile sperm yield (63.5 ± 18.2%), viable yield (60.9 ± 36.5%), and survival of progressively motile sperm after cooling (21 ± 10.8%) compared with noncentrifuged semen. In conclusion, centrifuging volumes of ≤ 20 mL minimized sperm losses with conventional protocols. With 40-mL columns, it may be recommended to increase the centrifugal force to 900 × g for 10 min and dilute the semen to a sperm concentration of 25 to 50 × 10(6)/mL in a milk- or fractionated milk-based medium. The semen extender VMDZ did not seem well suited for centrifugation of equine semen.

Effects of cooling time on membrane integrity and motility of frozen-thawed canine spermatozoa using two different commercial egg yolk-based extenders at two different cooldown equilibration times.

Two commercially available egg yolk-based semen extenders, one marketed for human semen freezing (HEYE) and one marketed for canine semen freezing (CEYE), were used to cryopreserve semen from single ejaculates of 11 different dogs. For each extender, a 30- and a 60-min cooldown period was used prior to the addition of the extender containing glycerol and then immediately frozen in liquid nitrogen vapours. Sperm motility was measured using a computer-assisted semen analysis (CASA) system. Sperm intact membranes were measured using SYBER-14 and propidium iodide. Semen in the HEYE cooled for 60 min had a significantly greater percentage of intact membranes than the semen in the HEYE cooled for 30 min (p = 0.02). Semen in the HEYE cooled for 60 min had significantly greater total motility (p = 0.007) and progressive motility (p = 0.004) than semen cooled for 60 min in the CEYE and semen cooled for 30 min in the HEYE (total motility p = 0.02 and progressive motility p = 0.02). Semen cooled for 60 min in the CEYE did not differ significantly in total (p = 0.6) or progressive motility (p = 0.4) than semen cooled for 30 min in the CEYE. There was no difference in total (p = 0.8) or progressive motility (p = 0.8) between the semen cooled for 30 min in the HEYE and the semen cooled for 30 min in the CEYE.

Persistent breeding-induced endometritis after hysteroscopic insemination in the mare.

Low-dose insemination has been proposed to reduce persistent breeding-induced endometritis (PBIE) in mares with delayed uterine clearance (DUC). Others proposed that hysteroscopic insemination induces an exaggerated inflammatory response and should be avoided in DUC mares. The objectives here were to evaluate presence and severity of PBIE in normal and DUC mares after hysteroscopic insemination with fresh semen, and to determine if hysteroscopy could be used in DUC mares without inducing excessive inflammation. Reproductively normal (n = 4) and DUC (n = 5) mares received four treatments in random order: uterine body insemination (UB, 1 × 10(9) spermatozoa, 20 ml), hysteroscopic insemination (HYST, 5 × 10(6) spermatozoa, 0.5 ml), sham hysteroscopic insemination (SHAM, semen extender, 0.5 ml) and hysteroscopic infusion of seminal plasma (SP, 0.5 ml). Significantly more DUC (50%) mares than normal (14%) mares accumulated intrauterine fluid 24 h post-treatment. The difference in fluid accumulation between DUC (40%) mares and normal (7%) mares was also significant 48 h post-treatment. Fluid scores were not significantly different between treatments in normal mares. However, treatments HYST and SHAM resulted in significantly higher fluid scores 24 h but not 48 h post-treatment in DUC mares. There was no effect of treatment or mare group on the percentage and total number of neutrophils in uterine fluid 48 h post-treatment. Percentage of neutrophils was correlated with duration of hysteroscopy in normal mares, with procedures lasting ≥ 9 min associated with PBIE. There was no effect of mare group, treatment or duration of hysteroscopy on pregnancy rate. Hysteroscopy induces a transient inflammation that is not more severe than that after conventional artificial insemination, suggesting no contraindication to its use in DUC mares.

Immediate and delayed (after cooling) effects of centrifugation on equine sperm.

The objectives of this study were to determine the effects of centrifugation on equine sperm total and progressive motility, viability, and acrosomal integrity. We hypothesized that although high centrifugation forces would be detrimental to equine Equus caballus sperm, recovery rates would increase. Ejaculates from six stallions were collected, extended to a concentration of 25x10(6) cells/mL, and subjected for 10min to (1) no centrifugation (NC) or (2) centrifugation at 400xg, (3) 900xg, or (4) 4500xg. Before and after centrifugation (Day 0), and after 24h of cooling (Day 1), sperm motility was assessed by computer-assisted semen analysis, and samples were stained with SYBR-14/propidium iodide (PI) for viability and with PI/fluorescein isothiocyanate (FITC)-Peanut aglutinin (PNA) (Arachis hypogaea) for acrosomal integrity. The effect of treatment and day on motility, viability, and acrosomal integrity was determined using a mixed linear model. Compared with the other treatments, centrifugation at 4500xg reduced all end points measured (P<0.05). Both 400xg and 900xg yielded lower recovery rates than that of 4500xg (NC=100.0+/-0.0%; 400xg=54.4+/-8.6%; 900xg=75.0+/-7.1%; 4500xg=97.9+/-2.8%; P<0.05). Centrifugation at 400xg or 900xg did not damage equine sperm. Based on these findings, further studies of centrifugal forces between 900xg and 4500xg are warranted to determine the optimal force that maximizes recovery rate, minimizes sperm damage, and does not affect fertility.

Scanning electron microscopy of the endometrium of mares infused with gentamicin.

Scanning electron microscopy (SEM) was used to study the endometrium of nine 1-year-old thoroughbred mares after twice intrauterine infusions of gentamicin, on 2 consecutive days. Five mares were infused on 2 consecutive days with 40 ml gentamicin (50 mg/ml) mixed with 80 ml of normal saline. Four mares served as controls and were infused with 120 ml of saline on 2 consecutive days. Endometrial biopsies were obtained from all mares 3 days after the second intrauterine infusion. Each biopsy was processed for SEM by standard methods. The endometrial epithelium of the gentamicin-infused mares had more cellular perforations than the saline-infused mares. The gentamicin-infused mares had less and shorter microvilli. The ciliated cells were fewer and some ciliated cells had disrupted and some had drooping cilia. The endometrial epithelium of the gentamicin-infused mares had a considerable number of endometrial cells that lost their luminal surfaces and some that lost their microvilli, compared to the saline-infused mares. We suggest that the information gathered in this pilot study should be used as basis for further investigation, on a larger scale basis, of the effects of repeated intrauterine infusion of gentamicin on the endometrial mucosa of mares.

Concentrations of nitric oxide in equine preovulatory follicles before and after administration of human chorionic gonadotropin.

In the present study, follicular fluids of estrous mares treated with saline solution (Control) or nitric oxide synthase (NOS) inhibitors were analyzed for nitric oxide (NO), estradiol-17beta (E2) and progesterone (P4) concentrations before and 36h after administration of human chorionic gonadotropin (hCG). Follicular fluids obtained before (0h) hCG administration from control mares had lower concentrations of NO than those obtained 36h after administration of hCG (58.3+/-17.8 micromol versus 340.4+/-57.7 micromol; P<0.05). A similar pattern was also noted for intrafollicular P4 in control mares, which had lower concentrations of intrafollicular P4 before hCG than 36h post-hCG administration (P<0.05). As expected, E2 concentrations of control follicles sampled before hCG administration were higher than those sampled 36h post-hCG administration (P<0.05). However, the E2 concentrations in follicles of mares treated with the NOS inhibitors N(omega)-nitro-L-arginine methyl ester (L-NAME) or aminoguanidine (AG) did not decrease after hCG administration, unlike those in control mares (P>0.10). In addition, mares treated with NOS inhibitors had lower intrafollicular concentrations of NO and P4 than control mares, both before and after hCG administration (P<0.05). Increased intrafollicular concentrations of NO in control, hCG-stimulated mares provide evidence for the presence of an NO-generating system in the equine preovulatory follicle that is likely upregulated following administration of hCG.

Effect of nitric oxide synthase inhabitors on ovulation in hCG-stimulated mares.

Recent studies suggest that nitric oxide (NO) may have a role in regulating ovarian physiology. To investigate the role of NO during ovulation in mares, inhibitors of the nitric oxide synthase (NOS) were administered to estrous mares. Forty cycling mares (20 horses and 20 pony mares) were allotted to one of the three treatment groups. Once a follicle was at least 27 mm in diameter, but smaller than 35 mm, mares were given one of the following treatments: saline solution 0.9% (n = 20, w/v, i.v., every 12 h), Nomega-nitro-L-arginine methyl ester hydrochloride (L-NAME; n = 10, 148 micromol/kg, i.v., every 12 h), or aminoguanidine hemisulfate (AG; n = 10, 406 micromol/kg, i.v., every 12 h). When a follicle >30 mm was present on one of the ovaries, ovulation was induced with hCG (2,500 IU, i.v.). The median time of ovulation (+/-6 h) after hCG administration for the treatment groups was 42, 84 and 54 h for mares treated with saline solution, L-NAME and AG, respectively. There was no significant difference between the groups treated with AG or L-NAME (P = 0.06); however, these groups were different from the control group (P < 0.05). The delayed ovulation caused by the administration of NOS inhibitors suggests a role for NO in follicular growth and ovulation in horses.

Osmotic sensitivity of canine spermatozoa.

The objective of this study was to determine osmotic tolerance of canine spermatozoa. The study comprised three experiments: (1) spermatozoa suspended either in an egg yolk-citrate (EYC) extender or in Kenney skim milk extender were exposed to NaCl solutions ranging from 290 to 1500 mOsm; (2) spermatozoa suspended in EYC were exposed to 550 to 1500 mOsm solutions of glucose, galactose, or fructose; and (3) spermatozoa suspended in EYC or glucose-bovine serum albumin (G-BSA) were exposed to 0.6 M (approximately 900 mOsm) or 1.2 M (approximately 1600 mOsm) solutions of glycerol, ethylene glycol (EG), or dimethyl sulfoxide (Me(2)SO). In all experiments, motility and membrane integrity of spermatozoa were assessed after they were diluted into isotonic medium at 37 degrees C. Exposure of canine spermatozoa to solutions of either NaCl or monosaccharides at osmolalities >500 mOsm caused a significant reduction of motility (P<0.01). Motility of spermatozoa was more affected by osmotic stress than their membrane integrity. Osmotic sensitivity of canine spermatozoa was dependent on the type of extender; spermatozoa suspended in the Kenney extender were more resistant to osmotic stress than those suspended in the EYC extender. Despite their sensitivity to exposure to high concentrations of nonpermeating agents, canine spermatozoa were rather resistant to exposure to glycerol and EG. However, Me(2)SO was toxic to canine spermatozoa; motility was substantially reduced after spermatozoa were exposed to 0.6 M Me(2)SO. The type of extender also affected the sensitivity of canine spermatozoa to Me(2)SO; spermatozoa suspended in the EYC extender were more resistant than those suspended in G-BSA. It was concluded that canine spermatozoa are sensitive to osmotic stress, but are tolerant to shrinking and swelling caused by exposure to permeating cryoprotectants.

The effects of ph, osmolarity and urine contamination on equine spermatozoal motility.

Urospermia has been reported as a cause of infertility in numerous species. The detrimental effects of urine on spermatozoa are due, at least in part, to changes in pH and osmolarity. Semen was collected and subjected to conditions of varying pH (Experiment 1), of varying osmolarity (Experiment 2), and various quantities and concentrations of urine (Experiment 3) and effects on motility were recorded. Finally, semen was contaminated with urine and then either of 2 semen extenders was added, with or without centrifugation, in an attempt to alleviate the detrimental effect of urine on motility (Experiment 4). The results of these experiments showed that alterations in pH and osmolarity negatively affected stallion sperm motility. Optimal pH and osmolarity appeared to be approximately 7.7 and 315, respectively. Contamination of the ejaculate with urine significantly decreased sperm motility. Smaller quantities of dilute urine were less detrimental than larger quantities of dilute urine, and dilute urine was less detrimental than more concentrated urine. The addition of semen extender restored the motility of urine contaminated semen to that of the uncontaminated control, however centrifugation to remove urine provided no significant advantage.

Anti-sperm antibodies and seminal characteristics after testicular biopsy or epididymal aspiration in dogs.

A study was performed to determine if performing testicular biopsies or epididymal aspirates in dogs would induce sperm-bound anti-sperm antibodies (ASA), affect long-term sperm production or semen quality. Semen was collected from 8 mature dogs 3 times a week before and after hemicastration and then 3 times a week after testicular biopsy (n=3 and 1 control) or epididymal aspiration (n=3 and 1 control). Detection of anti-sperm IgG (ASA) on sperm cells was performed by flow cytometry analysis using a flow cytometer. Two dogs with testicular biopsies became positive for ASA 16 d after testicular biopsy and remained positive for 7 and 9 d, respectively. One dog that had an epididymal aspirate became positive 13 d after epididymal aspiration and remained positive for 35 d. One dog became positive 21 d after hemicastration and remained positive for 28 d. Sperm output declined significantly in 7 of 8 dogs after hemicastration. A control epididymal aspirate treatment dog had decreased sperm output, and a testicular biopsy treatment dog had increased sperm output. None of the dogs with ASA had significant changes in sperm output after treatment. Sperm motility declined significantly in 3 dogs after hemicastration. An epididymal aspiration treatment dog had a decrease in sperm motility, a control epididymal aspirate treatment dog and a control testicular biopsy treatment dog each had increases in sperm motility. None of the dogs with ASA had significant changes in motility. The percentage of normal spermatozoa significantly decreased in 3 dogs and significantly increased in 1 dog after hemicastration. Two dogs that had testicular biopsies and 1 dog that had an epididymal aspiration had decreases in percent normal sperm. Two of 3 dogs with decreases in percent normal sperm after treatment had ASA, but 2 dogs with ASA had no change in motility. Hemicastration, epididymal aspiration, and testicular biopsy can induce ASA production within 2 wk of the procedure, but ASA are transient and do not have a predictably negative effect on total sperm output or motility. Testicular biopsy and epididymal aspiration are safe diagnostic procedures, but further work investigating post-treatment fertility must be done before final conclusions can be made.

Fertility in bitches artificially inseminated with extended, chilled semen.

Sixteen bitches were artificially inseminated with either fresh, 24 h-chilled or 48 h-chilled extended semen over 38 estrous cycles. A commercial system for extending, chilling and transporting semen commonly used in the equine industry was used Pregnancy rates and litter sizes of the bitches inseminated with extended, chilled semen (19/20, 95%; litter size = 7.1) were not significantly different from those observed in bitches inseminated with fresh semen (17/18, 94%; litter size = 7.2; P > or = 0.89). These results show that a commercial system for extending, chilling and transporting equine semen is an attractive and efficient method of shipping canine extended chilled semen.

The effect of reducing hindquarter elevation time after artificial insemination in bitches.

Hindquarter elevation time after artificial insemination in dogs was reduced from the common and arbitrarily used 10 min to only 1 min after insemination. Artificial insemination with fresh undiluted semen was conducted in 32 breedings using 15 hound bitches. The overall pregnancy rate was 91% (29/32), with an average litter size of 7.35 puppies per pregnancy. The pregnancy rate was not altered by reducing the 10-min (n = 14) hindquarter elevation time to 1 min (n = 18; P = 0.30). Similarly, the litter size was not different between groups (P = 0.40).

Effects of follicular aspiration and flushing, and the genotype of the fetus on circulating progesterone levels during pregnancy in the mare.

When aspirating ovarian follicles in pregnant mares to obtain oocytes for in vitro fertilisation (IVF), the effect of the manipulation on circulating concentrations of progesterone may be an important consideration in terms of the maintenance of pregnancy. The object of this study was to compare the effects of 3 different forms of transvaginal ultrasound-guided follicle aspiration (Treatment 1, no aspiration, n = 4; Treatment 2, aspirate only follicles > or =20 mm in diameter, n = 7; Treatment 3, aspirate all visible follicles, n = 7) on peripheral plasma progesterone concentrations between Days 21 and 150 of gestation in 9 mares carrying intraspecies horse and 9 mares carrying interspecies mule conceptuses. The 3 follicle aspiration treatments were applied at the peak of each follicular wave as determined by follicular mapping by means of transrectal ultrasonography on alternate days. The plasma progesterone profile in mares undergoing Treatment 1 was in close agreement with those reported previously in pregnant mares. A decline in plasma progesterone levels occurred after Day 53 of gestation in Treatments 2 and 3 mares, indicating that the follicular aspiration procedures did interfere with the formation of secondary corpora lutea. However, the levels in individual mares never dropped low enough to endanger the pregnancy. Mares carrying mule pregnancies exhibited higher mean plasma progesterone concentrations between Days 39 and 45 of gestation than mares carrying horse pregnancies, equivalent levels between Days 46 and 66 despite the lower circulating concentrations of chorionic gonadotrophin (mule CG) in their blood during this period and lower progesterone levels between Days 67 and 150 of gestation. The results indicate that the primary corpus luteum in the pregnant mare may be more sensitive to mule CG than horse CG. Furthermore, the earlier disappearance of CG from the circulation in mares carrying mule fetuses is reflected by an earlier decline in plasma progesterone concentrations in this type of equine pregnancy.

The use of ally-trenbolone as a progestational agent to maintain pregnancy in ovariectomized bitches.

The administration of the synthetic progestogen, allytrenbolone, at a dose of 0.088 mg/kg/d per os successfully maintained pregnancy in 3 of 3 bitches ovariectomized at 34 to 42 d of gestation and in 1 of 3 ovariectomized on Day 8 or 9 of gestation. However, a dose of 0.044 mg/kg/d per os maintained pregnancy in only 2 of 6 bitches ovariectomized in mid-gestation. Two bitches that had ovariectomies performed on Day 9 of gestation and were supplemented with ally-trenbolone at a dose of 0.088 mg/kg/d per os did not establish a pregnancy that was detectable by mid-gestation. Although inhibited the first 2 d post partum in some bitches, lactation increased sufficiently to successfully maintain pups.

Ultrasonic measurement of canine testes.

The goals of the present study were to determine if ultrasonic measurement of testicular dimensions (length, width, and height) would provide an accurate assessment of canine testicular size (weight) and to determine the relationship of these measurements to animal body weight. The bodies of 30 intact male dogs of unknown health, breed or breeding history were obtained after the dogs were humanely killed at the local animal shelter. Total scrotal width (TSW) was measured by calipers and the length, width and height of each scrotal testis, excluding the epididymis, were measured by sonography. The testes were then excised and weighed, again excluding the epididymis. Multiple regression was used to predict total testicular weight from 1) only sonographic measurements (Model 1), 2) all testicular measurements (Model 2), 3) only total scrotal width (Model 3), and 4) only body weight (Model 4). In addition, stepwise multiple regression was used to identify models (Models 5 and 6) using external measurements of the testes which seemed most useful in predicting total testicular weight. Models 1, 2, 3, 4, and 6 yielded r(2) values 0.90, 0.94, 0.88, 0.48 and 0.95 respectively. Model 5 yielded an r(2) of 0.90, but the additional accuracy achieved by using the testicular height was minimal. Although sonographic testicular measurement accurately predicted testicular weight, the small degree of additional accuracy achieved over TSW measurement by calipers does not justify the use of sonography in each case. However, if a testicular ultrasound scan is being performed, the ultrasonic measurements could be used to predict testicular weight.

Seminal vesiculitis as a cause of signs of colic in a stallion.

A 5-year-old stallion was referred because of signs of abdominal pain. During the initial examination, signs of pain were elicited when the right seminal vesicle was palpated per rectum. Signs of pain were also elicited during sexual arousal and attempts at semen collection. The right seminal vesicle was subsequently determined to be abnormal by ultrasonographic and endoscopic examination. The stallion was treated with trimethoprim/sulfamethoxazole for 6 weeks. Five months later, there had been no recurrence of the condition.

Diskospondylitis associated with Brucella canis infection in dogs: 14 cases (1980-1991).

A retrospective study of 135 dogs with diskospondylitis revealed 14 dogs with concurrent Brucella canis infection. Sexually intact male dogs and dogs in the southeastern United States appeared to be at higher risk. Results of bacteriologic culturing of blood were less likely to be positive for dogs with diskospondylitis caused by B canis infection than for dogs with diskospondylitis caused by other organisms. Follow-up evaluation of 13 of the 14 dogs revealed complete remission of clinical signs in nine, but serologic test results continued to be positive for B canis infection long after resolution of clinical abnormalities. Radiographic follow-up evaluation in 6 dogs revealed active lesions despite complete remission of clinical abnormalities.